A、are done in a week B、aren’t very clear C、are done in 24 hours D、take a long time C数字信息的找寻和判断。根据原文可知，若教师在www．plagiarism.com注册接受

There student thieves look out. Students can easily get many research papers off the Internet. A new Website could help teachers catch copiers.
    Some students research and write their term papers. Others, however, just copy them off the Internet and turn them in as their work.
    Two graduate students at the University of California at Berkeley have written a program to catch the students who copy. It compares a student’s paper with every other term paper on the Web.
    A hundred million Web pages on the Internet are searched. The top 20 search engines are used for the search. This service can be found at www. Plagiarism.com. They also have a local database of term papers. Teachers who sign up can send their students’ ’papers to the Website. Within 24 hours they know if the student did the work. Every sentence that was a word-for-word match with another sentence either found on the Internet or within our database is coded.
    A U. C. Berkeley professor told his class he would use the program. Still some students copied papers. All 300 papers went through the program. In 45 papers or 15 percent of students had cut and pasted large amounts of material from different World Wide Websites.
    Students that say they didn’t copy can defend themselves. They can show the instructor where they got their material. Students at universities try hard to get good grades. Some students welcome the Internet research watchdog because they say it is fair to all. They think copying is wrong.